1. The Field of the Invention
The present invention relates to vehicular safety. More specifically, the present invention relates to a novel apparatus and method for enhancing the flexibility and cost effectiveness of airbag systems without sacrificing protective capability.
2. The Relevant Technology
The inclusion of inflatable safety restraint devices, or airbags, is now a legal requirement for many new vehicles. Airbags are typically installed in the steering wheel and in the dashboard on the passenger side of a car. In the event of an accident, an accelerometer within the vehicle measures the abnormal deceleration and triggers the expulsion of rapidly expanding gases from an inflator. The expanding gases fill the airbags, which immediately inflate in front of the driver and passenger to protect them from impact against the windshield. Side impact airbags, known as inflatable curtains, have also been developed in response to the need for protection from impacts in a lateral direction, or against the side of the vehicle.
However, despite their enormous lifesaving potential, the use and effectiveness of known side impact airbags have been somewhat limited by a number of problems. One such problem is the speed with which inflation gases must fill the cushion to provide side impact protection.
Side impact cushions are often designed to unfold or unroll downward to inflate beside a person to keep the person from hitting the door or window during lateral impact. Since a vehicle occupant may be leaning forward, reclined in the seat, or at any position between, such cushions are often made somewhat long to ensure that the occupant hits the cushion. If multiple cushions are fed by a single inflator positioned either fore or aft of the cushions, an especially long gas flow path exists between the inflator and the cushion furthest from the inflator. Thus, the outermost extents of the inflatable curtain may receive insufficient inflation gas pressure to inflate to the optimal protective pressure.
Furthermore, the bulk and expense of known inflatable curtains limits the extent to which they can be utilized in compact and economy vehicles. Since each vehicle has a unique interior configuration, different inflatable curtain modules must often be designed for installation in each model. Manufacturing and inventory costs are increased by the necessary customization, particularly in the case of curtain modules in which multiple cushions are to be integrally formed with a single process. Such curtain modules are also inconvenient to ship.
Additionally, some known side impact systems simply are not sturdy enough to adequately protect vehicle occupants. Known cushions may move too much in response to the impact velocity of the vehicle occupant, particularly if there is no window or other surface to provide support for the cushion. Vehicle occupants may thus be injured despite the presence of the airbag.
If the curtain module is designed to provide rollover protection, another danger exists. Particularly in the case of more compact cushions, ahead or limb of an occupant may extend through an opening between or beside the cushion or cushions of the inflatable curtain module, and may then extend outside the vehicle during the rollover. xe2x80x9cOccupant excursionxe2x80x9d during rollovers is a common cause of automotive fatality, particularly in the case of vehicle occupants that are not wearing a seat belt during the rollover. Occupants can be jostled around considerably within the vehicle during a rollover; consequently, the positioning of cushions directly beside the vehicle seats may not be sufficient to protect against occupant excursion.
Accordingly, a need exists for an apparatus and method capable of enhancing the interchangeability of inflatable curtain modules. Furthermore, a need exists for an apparatus and method capable of supporting airbag cushions during impact to limit the degree to which such cushions are able to move from their deployed position. Yet further, a need exists for an apparatus and method capable of providing a greater degree of protection against occupant excursion, particularly during a vehicle rollover. Still further, a need exists for an apparatus and method capable of decreasing the cost, bulk, shipping expense, and/or installation expense of inflatable curtain modules.
The apparatus and method of the present invention have been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available inflatable curtains. Thus, it is an overall purpose of the present invention to provide an apparatus and method for enhancing the protective capability, interchangeability, flexibility, and economy of inflatable curtain modules.
According to one configuration, an inflatable curtain module according to the present invention may have two cushions configured to activate to shield vehicle occupants from impact against one or more lateral surface of the vehicle, such as doors and windows. For example, one cushion may be disposed beside a front seat, and the other cushion may be disposed alongside a rear seat. If desired, the cushions may be fed by different inflators, so that inflation gases do not need to travel through one cushion to reach the other. The cushions may be connected together by a tension coupling configured to transmit tension between the cushions and to act as a barrier to occupant excursion.
Each of the cushions may have a top edge and a bottom edge positioned on either side of a protection zone configured to hold the inflation gases. Furthermore, the top and bottom edges may be connected by interior longitudinal edges positioned toward the tension coupling and exterior longitudinal edges positioned away from the tension coupling.
According to one embodiment, the tension coupling may be affixed to the cushions prior to compaction of the cushions. The tension coupling may be affixed to the cushions by, for example, sewing each end of the tension coupling to an interior longitudinal edge of one of the cushions. The cushions and the tension coupling may then simply be compacted together, by folding, rolling, or the like. Thus, when the cushions deploy, the tension coupling may simply deploy in the same fashion.
In operation, the tension coupling may operate in conjunction with tethers that attach each cushion to the vehicle. When the cushions inflate, the cushions may shorten horizontally so that they pull tightly against the tethers. The tension coupling may then transmit the tension from the tethers between the cushions so that both cushions can be held tightly in the proper position against the lateral surface of the vehicle. Additionally, the tension coupling may provide a barrier between the cushions tending to keep the occupants inside the vehicle during a vehicle rollover.
In the alternative, the tension coupling may be configured to be attached to the cushions after the cushions are folded so that the inflatable curtain module can be constructed and shipped in a modular fashion. For example, according to one alternative embodiment, the tension coupling may have a compactible configuration that permits independent compaction and attachment to the cushions after the cushions have been compacted.
More specifically, the tension coupling may have a first expanse and a second expanse, each of which is configured to be attached to both cushions. The first and second expanses may be displaced somewhat from each other, and may be connected by an central portion capable of keeping body parts of vehicle occupants from extending between the first and second expanses after the curtain module has deployed. The central portion may be compacted, for example, through xe2x80x9caccordion typexe2x80x9d or xe2x80x9czig-zagxe2x80x9d folding (a folding pattern with adjacent folds in opposite directions) or rolling.
Each of the cushions may have one or more tabs protruding from the interior longitudinal edge. If desired, each cushion may have two tabs: one positioned at a location suitable for attachment to one of the expanses of the tension coupling. The tabs may protrude such that they remain exposed after compaction of the cushions.
Thus, attachment of the tension coupling to the cushions may be relatively easily accomplished after the cushions have been compacted by compacting the central portion to bring the first and second expanses closer together and then attaching each of the expanses between one pair of tabs, so that each expanse spans the gap between the cushions. Such attachment enables the cushions to be folded separately and, if desired, sent to the vehicle manufacturer in unattached form together with the tension coupling.
Attachment of the expanses to the tabs may be accomplished through the use of a wide variety of attachment mechanisms. For example, rigid mechanical fasteners, such as clamps, snaps, hooks, locking rings, screws, bolts, nuts, rivets, and tacks, may be used. If desired, each tab may have a hole positioned to align with a corresponding hole of the tension coupling so that a rigid mechanical fastener may be inserted through both holes and locked into place. Alternatively, the tabs may be sewn to the tension coupling. As yet another alternative, the tabs may be welded to the tension coupling through a method such as ultrasonic or RF welding.
The cushions may be folded in a variety of different ways, including accordion type folding and rolling. If desired, the tension coupling may be folded in the same manner to facilitate proper deployment. For example, if an accordion type fold is used for the cushions, the tension coupling may also have an accordion type fold, and may have the same number of folds as the portion of each cushion between the tabs. If the cushions are compacted by rolling, the tension coupling may also be rolled, and may have the same number of rolls as the portion of each cushion between the tabs.
In the alternative, the tension coupling may be compacted in a manner different from that used to compact the cushions. For example, an accordion folded tension coupling may be used in combination with rolled cushions, or a rolled tension coupling may be used in combination with accordion folded cushions. As yet another alternative, the tension coupling need not be compacted in any orderly fashion, but may simply be compressed to be stowed between the cushions.
In addition to the tabs, other methods may be used to attach a tension coupling between two cushions after the cushions have been folded. For example, each cushion may have an array of cushion holes formed proximate the interior longitudinal edge. The tension coupling may have two corresponding arrays of coupling holes. The holes of each array may be spaced apart such that the holes of each array of coupling holes can be aligned with the holes of an array of cushion holes.
After each array of coupling holes has been aligned with an array of cushion holes, some type of attachment mechanism may be utilized to attach each pair of aligned hole arrays. For example, a plurality of rigid mechanical fasteners may be inserted through each pair of aligned holes and locked into place. In the alternative, a lace may be inserted through all of the holes of each aligned pair of arrays so that the lace effectively interlocks with the cushion and the tension coupling to provide attachment.
The holes of each array may also be spaced apart to align with each other after compaction so that the lace can be inserted through all of the holes of each pair of arrays with one comparatively simple motion. Each lace may then be locked into place through the use of a stopper, such as a locking clamp.
Through the system and method of the present invention, an inflatable curtain module may be made with a plurality of interchangeable components, so that manufacturing, shipping, and storage costs for the airbag as a whole are reduced. The system and method disclosed herein may enhance the effectiveness of the inflatable curtain module through the use of the tension coupling to transmit tension between the cushions, thereby keeping the cushions in a highly protective location. Furthermore, the system and method of the present invention may more effectively prevent occupant excursion during vehicle rollovers by blocking the space between cushions with the tension coupling.
These and other objects, features, and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.